When Isilon Systems sold to EMC for $2.25 billion in December 2010, Isilon co-founder Sujal Patel made a pledge to stick around for two years or get the storage company to a $1 billion revenue run rate. Now, with Isilon creeping up on its two-year anniversary of the sale and on the path to hit the revenue milestone, Patel has decided to step aside from the company he co-founded 12 years ago.

What’s next for the entrepreneur? Another startup? Angel investing?

Well, first off, he plans to spend a good portion of his time on diaper duty. The 38-year-old father of twin 4-year-old boys has another baby on the way in December, making it a especially good time to step away from the day-to-day grind of running one of Seattle’s most successful tech operations.

“I’m going to change diapers. I am going to pursue personal pursuits, spend time with the family,” said Patel, who will remain as a consultant to EMC. “I’m going to recoup a little bit, and then we will see what goes on from there.”

Asked whether he’d consider doing another startup, the former RealNetworks engineer said “possibly.”

“There’s a ton of opportunities out there,” he said. “I love the region, so I want to do something here that continues to add to the entrepreneurial capability of the region, whether that’s a new startup or something else, who knows. We will see.”

The EMC Isilon S-Series Platform

Patel has already become a more active angel investor, with two deals expected to close in the next month and about a dozen in his portfolio from the past year. He’s also a board member at ExtraHop Networks, a Seattle startup backed by Madrona Venture Group, the venture firm that initially seeded Isilon.

Isilon is one of most groundbreaking technology companies to have emerged from Seattle in the past two decades. But the company almost didn’t make it after series of missteps following its December 2006 IPO, a period that Patel refers to as a “complete disaster.” That led to Patel returning as CEO and completely repositioning the business amid ongoing pressures from Wall Street.

Looking back over the past 12 years, Patel admits that the Isilon journey was a pretty “unbelievable experience.”

“We definitely have a lot of intriguing things in our 12-year history that added a lot of intrigue and interest,” said Patel. “Every experience that you have not only heartens you, but the whole company. And we had plenty of adversity over 12 years that we had to overcome.”

In an interview Tuesday at Isilon’s new Pioneer Square headquarters, Patel said the time was right to move on.

“The business is absolutely doing incredibly well, and the business is growing phenomenally,” he said. “And we have an organizational strategy and structure in place, so the timing is perfect for me after 12 years to step aside and let the next generation scale this thing from here.”

That responsibility falls into the hands of Bill Richter, a six-year veteran of Isilon who had served as CFO prior to the EMC acquisition. Richter said he’s excited about the prospects in front of Isilon, especially as trends such as cloud computing and big data continue to take off.

“The market of big data and scale-out is now here. It has come at us for the past couple of years, and now I’d say it is fully here,” said Richter, who is assuming the title of president of the Isilon storage division. “We’ve got a 12-year head start on most of the competition. When you think about it, what Sujal founded back in 2001, was an idea of a storage architecture for big data, ten years before we called it big data. So, we are pretty well positioned in that sense.”

Isilon also continues to expand at a rapid pace in the Seattle area. Its new headquarters in Pioneer Square is now spread across three floors, with the company on track to take over another floor later this year.

The Isilon unit employs about 1,200 people, with more than a third of those workers in Seattle.

“We are effectively hiring engineering talent in Seattle as fast as we can,” said Richter.

Asked about the biggest challenge facing Isilon as it enters the next phase, Richter noted that the company will have to continue to transform itself inside EMC.

“The world is transforming at a rate that is faster than ever before,” said Richter, adding that they are going to have to integrate with EMC technologies in ways that “were unimaginable a couple of years ago.”

John Cook is GeekWire's co-founder and editor, a veteran reporter and the longest-serving journalist on the Pacific Northwest tech startup beat. Follow him @johnhcook and email john@geekwire.com.